Field
The present invention relates to the field of automated, computerized driver assistance in air, land or sea vehicles, where a sensor of a host vehicle physically senses the environment of the host vehicle, and a computing unit, supplied with an output signal of the sensor, computes a signal which assists in the guidance of the host vehicle when supplied to optical or acoustical indication means and/or when being supplied to an actuator or a controller unit for controlling such actuator of the vehicle. The actuator of the vehicle might be a safety device (airbag, . . . ) or an actuator influencing the movement of the vehicle (flaps, brakes, accelerator, steering, . . . ).
Description of the Related Art
Driver assistance systems such as “Adaptive Cruise Control” (ACC) systems (e.g. described in ISO-Norm 15622:2010) increase driver comfort and safety. They are especially used for carrying out longitudinal control of a host vehicle, for example with respect to a velocity specified by the driver and ranging to other traffic objects such as other land, air or sea vehicles (cars, motorbikes, bikes, trucks, etc.), pedestrians, . . . . The host vehicle is provided with (“hosts”) a sensor physically sensing the host vehicle's environment and a computing unit processing an output signal of the at least one sensor.
One problem of commonly known driver systems is that usually the system takes into consideration only behavior of other traffic vehicles when the behavior can already be recognized (physical prediction). For example if one of the target objects (a vehicle in the environment of the host vehicle and physically sensed by one or more sensors of the host vehicle) changes the lane thereby cutting into the lane of the host vehicle or cutting out to another lane, the host vehicle which observes the other traffic vehicles only reacts after such lane change is certain. As a consequence, the reaction of the host vehicle is delayed which has a negative influence on the traffic flow and in particular on the comfort of the driver of the host vehicle.
In EP 2 562 060 A1 it was proposed to use in addition to a so-called physical prediction furthermore a context-based prediction. In such context-based prediction a probability of the future behavior of a target object is calculated. This future behavior is then confirmed or dismissed by the physical prediction. For calculating the probabilities of possible future behavior of the target objects, indirect indicators are used which do not only allow the observation of a behavior of the target object when it already has started. From the calculated probabilities, it is possible to recognize situations that make a particular behavior of the target objects likely to happen.
One problem of such approach is that for context-based prediction only the current situation of the traffic situation of the host vehicle is taken into consideration. Thus, at a particular point in time, the context-based prediction may for example give the result that a target vehicle which is on a neighboring lane will cut in the lane of the host vehicle because the target vehicle quickly approaches a predecessor vehicle. According to EP 2 562 060 A1, this will result in decelaration of the host vehicle, because in such a situation it is likely that the target vehicle will cut in to overtake the slower predecessor vehicle. But the situation that is the basis for such estimation in any case has a history. Firstly, it could of course well be that the target vehicle in fact was on the neighboring lane for a long time and therefore will in fact overtake the predecessor vehicle. But secondly, it could also be possible that in a situation previous to the one that is the basis for the context-based prediction, the target object was the predecessor of the host vehicle and in order to let the host vehicle overtake changed lane to the neighboring lane. As a result of this previous behavior, the target vehicle now quickly approaches its predecessor, but a probability that this target object again cuts in before it was overtaken by the host vehicle is rather low. The known context-based prediction therefore would deliver a wrong result.
According to previous proposals, no history is taken into consideration when an estimation for a future behavior of target objects is made. The quality of prediction of such systems is therefore quite limited.
It is hence an object of the invention to provide a method and system capable of alleviating the above problem.